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BRITISH FERNS . 
TUNBRIDGE HYMENOPHYLE, OR FILMY 
FERN. 
HYMENOPHYLLUM TUNBRIDGENSE, 
Smith, Hooker and Arnott, Bentham, Babington, Moore, and 
Newman. 
(Plate XI. Fig. 2.) 
SYNONYM. 
Trichomanes tunbridgense , Linnaeus. 
The filmy ferns are moss-like plants, the name is 
derived from two Greek words, signifying membrane 
and leaf. 
This little fern has a creeping root with minute 
twisted fibres. The fronds are not above two or three 
inches long, pinnate, lanceolate in general outline, and 
of an olive-brown tint. The veins are so strongly 
marked that they may be said to form the fronds, the 
leafy part being a very delicate membranous kind of 
wing on each side. The clusters of capsules are 
formed round the axis of a vein which runs beyond 
the margin of the frond: it is inclosed in a kind of 
cup which, forms the involucre. 
The tufts of this fern grow so closely together, and 
are of such a brown tint of colour, that they may 
almost be taken for a kind of moss, or for a withered 
plant. The whole family are the smallest of our 
native ferns, and although so delicate in form and 
texture, retain their appearance well, when dried, in 
the herbarium. Both species may be distinguished 
